若要求“查询选修了3门以上课程的学生的学生号”,正确的SQL语句是( )。
A. SELECT Sno FROM SC GROUP BY Sno WHERE COUNT(*)>3
B. SELECT Sno FROM SC GROUP BY Sno HAVING( COUNT(*)> 3)
C. SELECT Sno FROM SC ORDER BY Sno WHERE COUNT(*)>3
D. SELECT Sno FROM SC ORDER BY Sno HAVING COUNT( *)>= 3
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对下面的查询语句描述正确的是( )。SELECT StudentID,Name,(SELECT COUNT(*) FROM StudenExamWHERE StudenExam. StudentID=Student. StudentID AS ExamsTakenFROM StudentORDER BY ExamsTaken DESC
A. 从Student 表中查找StudentID和Name,并按照升序排列
B. 从Student表中查找StudentID和Name,并按照降序排列
C. 从Student表中查找StudentID、Name和考试次数
D. 从Student表中查找StudentID、Name井从StudenExam表中查找与StudentID一致的学生考试次数,并按照降序排列
在学生选课表(SC)中,查询选修20号课程(课程号CH)的学生的学号(XH) 及其成绩(GD)。查询结果按分数的降序排列。实现该功能,正确的SQL语句是()。
A. SELECT XH,CD FROM SC WHERE CH=’20’ ORDER BY GD DESC;
B. SELECT XH,CD FROM SC WHERE CH=’20’ ORDER BY GD ASC;
C. SELECT XH,CD FROM SC WHERE CH=’20' GROUP BY GD DESC;
D. SELECTXH CD FROM SC WHERE CH=’20’ GROUP BY GD ASC;
现要从学生选课表(C)中查找缺少习成绩(G)的学生学号和课程号,相应的SQL语句如下, 将其补充完整:SEECT S#, C# FROM SC WHERE ( )
A. G=0
B. G<=0
C. G= NULL
D. G IS NULL
SELECT * FROM city LIMIT 5, 10描述正确的是()
A. 获取第6条到第10条记录
B. 获取第5条到第10条记录
C. 获取第6条到第15条记录
D. 获取第5条到第15条记录
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